Gastric cancer is one of the deadliest and most diagnosed cancers, although the annual incidence has been steadily decreasing. Gastric cancer risk is multifactorial with a clear association with Helicobacter pylori infection. In the United States, the age-adjusted annual incidence is 4.1 per 100,000 people with a mortality rate of 1.6; the global adjusted annual incidence is roughly twice as much with a mortality rate four times higher. No randomized controlled trials have demonstrated the benefit of endoscopy or serum pepsinogen measurement in screening for gastric cancer. Patients are often asymptomatic or have general symptoms such as weight loss, abdominal pain, nausea, and anorexia, which can preclude an early diagnosis. When gastric cancer is suspected, the recommended initial test is upper gastrointestinal endoscopy with multiple tissue biopsies. A multidisciplinary treatment team should be assembled, and shared decision-making should occur with consideration of cancer staging, comorbidities, and available treatments. Treatment is guided by extent of disease, histopathology, and tumor biomarkers. Chemotherapy and radiation, in addition to various targeted therapies, may be treatment options for tumors regardless of resectability. Prognosis is directly related to the extent of disease at diagnosis; the 5-year survival rate of treated localized disease is more than 70% vs less than 10% for distant metastatic disease.
Globally, gastric cancer is the fifth most diagnosed and fourth deadliest malignancy. It occurs less frequently in the United States, where it is the 16th most diagnosed and 17th deadliest malignancy.1–4
SORT: KEY RECOMMENDATIONS FOR PRACTICE
| Clinical recommendation | Evidence rating | Comments |
|---|---|---|
| Patients whose family history suggests the possibility of a heritable syndrome associated with gastric cancer should be referred to a geneticist.5,20 | C | Consensus guidelines and expert opinion |
| Endoscopic evaluation with at least five to eight biopsies should be performed in patients with suspected gastric cancer.5 | C | Consensus guidelines and expert opinion |
| Palliative care should be individualized for each patient based on cancer stage, comorbidities, and personal preferences.4 | C | Consensus guidelines and expert opinion |
| Palliative care should include dietary education and counseling, psychological support services, symptom palliation, and surveillance for recurrence.5 | C | Consensus guidelines and expert opinion |
A = consistent, good-quality patient-oriented evidence; B = inconsistent or limited-quality patient-oriented evidence; C = consensus, disease-oriented evidence, usual practice, expert opinion, or case series. For information about the SORT evidence rating system, go to https://www.aafp.org/afpsort.
EPIDEMIOLOGY
- More than 90% of gastric cancers are adenocarcinomas.5
- Globally, more than 1 million cases occur each year.6
- Gastric cancer has a male to female ratio of roughly 2: 1,6 and it is relatively rare in people younger than 45 years, with an annual incidence of less than 1 case per 100,000 people.7 In the United States, the average incidence in White people is roughly one-half of the incidence in people who are Asian/Pacific Islander, Black, Indian/Alaska Native, or Hispanic, for unclear reasons.8
- More than two-thirds of diagnoses occur in Asia, with the age-adjusted annual incidence in Eastern Asia of 16.1 cases per 100,000 people.2,3,6 The lowest rates occur in Africa (4 cases per 100,000 people with a mortality rate of 3.5) and the United States (4.1 cases per 100,000 people with a mortality rate of 1.6).6
- The annual incidence of gastric cancer has decreased over the past century due to improved sanitation, which has lowered rates of Helicobacter pylori infection (a clear risk factor for gastric cancer).9–11
- Risk factors and protective factors for gastric cancer are outlined in Table 1.12–18 Obesity, gastroesophageal reflux disease, and hiatal hernias appear to increase risk of cancer in the gastric cardia (proximal to the esophagus); this increase is most commonly seen in Western countries with higher income.5,19
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